题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=3555
同理不要62，这回是要求带49的数，那么先求出不带49的，再减去。
1 #include <bits/stdc++.h> 2 using namespace std; 3 #define fr first 4 #define sc second 5 #define cl clear 6 #define BUG puts("here!!!") 7 #define W(a) while(a--) 8 #define pb(a) push_back(a) 9 #define Rint(a) scanf("%d", &a) 10 #define Rll(a) scanf("%I64d", &a) 11 #define Rs(a) scanf("%s", a) 12 #define Cin(a) cin >> a 13 #define FRead() freopen("in", "r", stdin) 14 #define FWrite() freopen("out", "w", stdout) 15 #define Rep(i, len) for(int i = 0; i < (len); i++) 16 #define For(i, a, len) for(int i = (a); i < (len); i++) 17 #define Cls(a) memset((a), 0, sizeof(a)) 18 #define Clr(a, x) memset((a), (x), sizeof(a)) 19 #define Full(a) memset((a), 0x7f7f7f, sizeof(a)) 20 #define lrt rt << 1 21 #define rrt rt << 1 | 1 22 #define pi 3.14159265359 23 #define RT return 24 #define lowbit(x) x & (-x) 25 #define onecnt(x) __builtin_popcount(x) 26 typedef long long LL; 27 typedef long double LD; 28 typedef unsigned long long ULL; 29 typedef pair<int, int> pii; 30 typedef pair<string, int> psi; 31 typedef pair<LL, LL> pll; 32 typedef map<string, int> msi; 33 typedef vector<int> vi; 34 typedef vector<LL> vl; 35 typedef vector<vl> vvl; 36 typedef vector<bool> vb; 37 38 const int maxn = 25; 39 40 LL digit[maxn]; 41 LL dp[maxn][2]; 42 43 LL dfs(int l, bool num, bool jud) { 44 if(l == 0) return dp[l][num] = 1; 45 if(!jud && ~dp[l][num]) return dp[l][num]; 46 LL ret = 0; 47 int nex = jud ? digit[l] : 9; 48 Rep(i, nex+1) { 49 if(num && i == 9) continue; 50 ret += dfs(l-1, i==4, jud&&i==nex); 51 } 52 if(!jud) dp[l][num] = ret; 53 return ret; 54 } 55 56 LL f(LL num) { 57 int pos = 0; 58 while(num) { 59 digit[++pos] = num % 10; 60 num /= 10; 61 } 62 return dfs(pos, false, true); 63 } 64 65 LL n; 66 67 signed main() { 68 //FRead(); 69 Clr(dp, -1); 70 int T; 71 Rint(T); 72 W(T) { 73 cin >> n; 74 cout << n - f(n) + 1 << endl; 75 } 76 RT 0; 77 }